* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: Inter, "Segoe UI", sans-serif;
  background: linear-gradient(135deg, #0f172a 0%, #111827 40%, #1d4ed8 100%);
  color: #e2e8f0;
}

.page-shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 2rem;
}

.card {
  width: min(100%, 680px);
  background: rgba(15, 23, 42, 0.72);
  border: 1px solid rgba(148, 163, 184, 0.24);
  border-radius: 24px;
  box-shadow: 0 24px 60px rgba(15, 23, 42, 0.4);
  backdrop-filter: blur(12px);
  padding: 2rem;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.72rem;
  color: #93c5fd;
  margin: 0 0 1rem;
}

h1 {
  font-size: clamp(2rem, 4vw, 3.2rem);
  line-height: 1.1;
  margin: 0 0 1.25rem;
}

.shortener-form {
  display: grid;
  gap: 1rem;
}

.field-group {
  display: grid;
  gap: 0.5rem;
}

label {
  font-weight: 600;
  color: #dbeafe;
}

input[type="url"], input[type="text"] {
  width: 100%;
  border-radius: 14px;
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: rgba(15, 23, 42, 0.8);
  color: #f8fafc;
  padding: 1rem 1rem;
  font-size: 1rem;
}

input[type="submit"], .action-link {
  appearance: none;
  border: none;
  border-radius: 14px;
  background: linear-gradient(135deg, #60a5fa 0%, #2563eb 100%);
  color: white;
  font-weight: 700;
  padding: 0.9rem 1.2rem;
  font-size: 1rem;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: transform 150ms ease, box-shadow 150ms ease;
}

input[type="submit"]:hover, .action-link:hover {
  transform: translateY(-1px);
  box-shadow: 0 12px 24px rgba(59, 130, 246, 0.38);
}

.status-card {
  text-align: center;
}

.status-card p {
  color: #cbd5e1;
}

.error-box {
  margin-bottom: 1rem;
  padding: 0.9rem 1rem;
  border-radius: 12px;
  border: 1px solid rgba(248, 113, 113, 0.6);
  background: rgba(127, 29, 29, 0.25);
  color: #fecaca;
}

.error-box ul {
  margin: 0;
  padding-left: 1.1rem;
}

.success-box {
  margin-top: 1.5rem;
  padding: 1rem 1rem 0.25rem;
  border-radius: 18px;
  border: 1px solid rgba(96, 165, 250, 0.45);
  background: rgba(30, 41, 59, 0.7);
}

.success-label {
  margin: 0 0 0.75rem;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: #93c5fd;
}

.success-row {
  display: flex;
  gap: 0.75rem;
  align-items: center;
}

.short-url-input {
  flex: 1;
  min-width: 0;
}

.copy-button {
  border: none;
  border-radius: 12px;
  background: #2563eb;
  color: white;
  padding: 0.85rem 1rem;
  font-weight: 700;
  cursor: pointer;
}

@media (max-width: 640px) {
  .card {
    padding: 1.25rem;
    border-radius: 18px;
  }

  h1 {
    font-size: 2rem;
  }

  .success-row {
    flex-direction: column;
    align-items: stretch;
  }
}